Pneumatic siren



Feb. 24, 1948 D. D RITCHE'Y 3 PNEUMATIC SIREN Filed May 15, 1943 4 Sheets-Sheet l Feb. 24, 1948. D. D.YRITCHIEY 2,436,603

PNEUMAT I C S IREN Filed May 15, 1943 4 Sheets-Sheet 5 Feb. 24, 1948. D. D; RITCHEY PNEUMATIC SIREN Filed May 15, 1943 4 Sheets-Sheet 4 Patented Feb. 24, 1948 UNITED STATES PATENT OFFICE I This invention relates to a sound device and has particular relation to a device which provides interrupted sound.

It has been found that with the usual warning devices used as alarms as, for example, the sirens on emergency vehicles, there has been considerable confusion, particularly in trafiic, due to the fact that a continuous uninterrupted noise will not attract the attention of persons whose minds are occupied as by the safety of the pedestrians on the street.

It has been found that since no attention is paid, by the average motorist, to the noise from the gearing of a heavy truck or bus, when the siren of an approaching emergency vehicle is heard at a distance, it does not register as a warning noise.

I have discovered that a continual interrupted noise is quickly distinguished from the noise of a gearing and that motorists react at once when such a noise is heard. I

The primary object of this invention is the provision of an improved sound device having an interrupted tone to more pointedly attract the hearers attention without increasing the volume.

Another object of the invention is the provision of an improved sound device wherein the sound is interrupted at predeterminedintervals for a given set of conditions.

A further object of the invention is the provision of an improved sound device having automatically operated valve, means rapidly increasing and decreasing the area of the admission opening of a siren.

Still another object of the invention is the provision of an improved sound device having pneumatically operated valve means to control the mer position after the controller has moved in the opposite direction.

tion is the provision of a sound device having electro-magnetic means for controlling the operation of a valve and electric means for controlling the electro-magnetic means.

Other and further objects of the invention will 7 be apparent to those skilled in the art from a operation of the sound device interruptedly. A i

still further object of the invention is the provision of an improved sound device having pneumatically operated valve means for controlling the opening of the valve means and resilient means for closing the same.

Another and still further object of the invention is the provision of an improved sound device wherein a siren is provided with a, valve for controlling the passage of air therethrough and pneumatic controller means operated by the partial vacuum created within the siren.

Another and still further object of the invention is the provision of an improved sound device wherein a siren is provided with a valve controlling the passage of air therethrough with pneumatic controller means for moving the valve quickly after a given movement is-made'in one direction, and for returning the valve to its forreading of the complete specification.

Referring now to the drawing wherein are illustrated various types of modifications of the invention.

Fig. 1 is a partial cross section of a modification of the invention which utilizes the partial vacuum created by the siren to operate the control valve.

Fig. 2 is a side view of the structure shown in Fig. 1 with the controller pneumatic expanded, but with parts cut away.

Fig. 3 is a view similar to Fig. 2 with the controller pneumatic collapsed.

Fig. 31; is a modified form of a device to draw air from and admit air to the controller pneumatic of Figs. 1 to 3.

Fig. 3b is another form of the structure of Figs, 1, 2 and 3. Fig. 4 ma front view of a modified form of valve and valve control as operated electricaliy instead of pneumatically, with the casing removed.

Fig. 5 is a view similar to Fig. 4 but illustrating the shutters in the open position.

Fig. 6 is a side view of Fig. 4 but with the cover shown sectionally.

Fig. 7 is a partial sectional elevational view of a modification of the invention wherein a reversing mechanism similar to the usual windshield wiper motor is used.

Fig. 8 is a top plan view of Fig. 7.

Fig. 9 is a side view of a modified form of the invention using two cam-controlled valves.

Fig. 10 is a view'of Fig. 9 from the right.

Figs. 11 and 12 are side and front views, respectively, of another modification.

Similar reference characters refer to the same or similar parts throughout the specification and drawing. 7

Referring particularly to Figs. 1 to 3, 20 designates the motor and 2| the siren interrupter of the siren. To the intake side of the siren stator provided with apertures in its periphery is secured a plate 22 which may extend over the 3 edge of the siren stator. The plate 22 is provided with lugs 23 for securing the plate in place on the siren stator.

To the side of the plate 22 is secured the stationary member 24 of the pneumatic controller 25. Hinged to the member 24 by the hinge 26 is a movable member 21 of the controller 25. On the outer side of the movable member 21 is a post 28. f

A tubular member 29 is secured within an opening of the stationary member 2d and opens into the intake of the siren. Within the tubular member 29 is pivotally mounted the valve 30 having an extension extending through the wall of the tubular member 29 and of suficient lengtl'i to provide an operating end 3!. To this operat; ing end 3! is secured the bell crank arm 32 which when moved, moves the valve 30 on it's'pivo'ts'. Secured at one end to the crank arm 32 is the en ion r n The. o po i e nd o h p in 33 is secured to the post 28 at a notch 2.8a. The os ion th catch i pre era ly. at a poin Wh r h prin 3 Wi v ake. the. same an l with the crank arm 32 whether. he pneumatic. controller is at the limit of movement in either t nde Q o l sed po t on. When t e pn m t nt o er. s co sed the rin will be on one side oi the valve axis and when expanded, it will be on the oth l'. Side.

With this construction, a predetermined movement of the pneumatic controller movable member 2l takes place before the valve moves. As the axis of the spring 33 is moved by, the pneumaticcontroller past the valve axis, the spring 33 acts to move-the valve quickly from one limit of movement to its opposite limit of movement. These limits of movement may be when the valve l lv Op r.. ul y. lo eduitable stops. 3 and 35 are provided to stop the valve at. either. open or closed position.

t s t b n ed h t. hepowerrn i is circular in outline. In order to gain. the. greatest area and therefore the greatest power. the movable member 0i theprleumatic controller surrounds the tubing 29,; and has, an opening a n hio P s ve i dplea the bi 291' and pivot on its hinge 2 6 with sufficient. clearance. To seal the space between the outside of the tubing 29 andthe opening inthemovable part of the pneumatic controller, bellows mate: rial'is "secured to the edgeoi the openning in the movable member and alsoto thetubing member 29; as shown at 34. This construction per: mits the pneumatic controller to be practically the size of the siren statorwithout protruding much at the sides' nsdob One way to exhaust the alr flplllthe pneumaticcontroller isbya controllable valve device 3'l having a screw valve 31. wl ich by adjustment will control the exhaust from the, power con: troller toth'e tubing 29 and thence to the rotor. of the siren. V

By this construction, as soon as the siren is started, thereisatendeneyto drive the air out. at the periphery of the siren stator by centrifugal force but wlththe' valve 3Q c losed, the air is prevented from 'escapingthrough. the, siren.

stator. This exhaust tendency. BlSljlfEillStS air through the valve device 31, thus collapsing the pneumatic controller. As the movable member 21 moves the spring 33 over the center, thevalve is quickly opened." This destroys the' vacuum in the tubing 29; permits the air'to pass and sounds the siren.

However as soon a's the yacuutn in the tubing 29 is destroyed the air begins to enter the pneu: matic controller through the valve device 31 and the return spring 38 expands the pneumatic controller, returning it to its normally expanded position. As the spring 33 again passes the valve axis, the arm 32 is moved to the other limit of movement and the valve is quickly closed. Again vacuum. is built up and the cycle is repeated. The closing of the valve interrupts the flow or air' and'its opening permits the flow to start. In this way, the valve opens and closes alternately and starts or stops the sound of the siren, almost instantaneously. By this construction a very unique alarm is sounded-one which is not easily mistaken for other noises of machinery oi automotive vehicles which may be met in the streets. By varying the point of holding the spring 33 -on the post 23 and the setting of the screw valve 21a and the tension of the spring 38, the frequency. of cycle may be controlled. A casing 4.0. is secured in place'by the screws Alla and breathing holes 4| are provided to give the pneumatic controller free. movement.

Fig. 3c is. a fragmental sketch. showing a modi-.v fied form of the inlet and outlet control of air to. and from the pneumatic controller 25. As illustrated, the pneumatic controller 25 has been. collapsed and is about to. cause, the bell crank lever 32 totrip from its position as shown and move to the position illustrated in Fig. 3. This causes a pushon the rodR which is ivoted to hebe l-mia k e e 3 The lower end; of; the rod R is pivoted to a swinging valvev whiclris. pivoted on a block B at the pivot 1?. The free endof this valve V in one position, as illustrated in full lines, covers an openingin the block B which is connected to the q illt A. to. atmosphere. In. dotted position. the valve V coversthe opening E which is connected to the intake manifold of an internal combustion motor orany other source of vacuum.

As the valve 3jlismovedby the bell crank lever 32, the .latter alsornoves the valve V to its other extreme, thus, alternately, connecting the openingsA and E' to thejnterior. of the pneumatic controller 25.:

The openingE is. opened to theinterior of the pneumatic controller 25; asthe latter approaches I, the pointoi greatestexpansion. Atthe same time 50' the atmosphe ric; port A is. closed. The air now beginsto exhaust from the pneumatic controller.

2tl-and collapsethe same, As the pneumatic controller approaches the position shownin Fig. 3a, the valve V-willoperate from. full line position to dotted posit qr l. This will connect the interior of the pneumatic controller 25 to the atmosphere by the conduit. A; and. the spring 38'. will cause the pneumatic. controller. 25 to expand. On reaching expandedposition another cycle will en;

In Fig. 3btheyalveWisdirectly connected to and is controlled by thevalve 30.to open and close the port to latmo phere this action correspondillg, to the aetion of. the .valve Vand port A, already described.

Any. suitablemain cut .oitvalvemaybe used on the exhaust connection. E. either -in connection with or independent of .the switch controlling thepower to the motor .20

In, the.embodimentillustrated in Figs. 4, 5 and 6,. I2lldesignates .the plate.whichicorresponds to the plate22 (ii-Fig.1 and is secured. to thesiren stator l2l.as by suitablelugs I22.- I V In this ,iorm, there are a. plurality of shutters which .op rate'as acv'alve; These shutters I23 are pivoted in angles I24 which are secured. to the plate I2I at the sides of the Opening la. The shutters I23 are provided at one end, each with a small crank 123a. These cranks are all controlled by a single bar or link I25. The link I25 has at one end a spring I26 which is, at its other end secured to a bracket I21 mounted on the plate I20. 1

To the opposite end of the link I24 is connected a small spring I28 which is connected to a movable member I29 of the solenoid I30. The solenoid I30 is connected on one side, electrically, to a thermostatic control member I3I which peri-' odically connects and disconnects the current. When the switch (not shown) is closed, the control member I3I connects and disconnects automatically, the current to the solenoid, thus operating periodically the shutters I23. As the current is cut off, the spring I26 at once operates to move the link I25 and close the shutters. If desired, the terminals of the thermostatic control and the solenoid may be connected to the switch which controls the operation of the siren motor. Or, if desired, a separate switch may be used. As these switch devices are not, per se, part of this invention, they will not .be further described.

The casing I32 with its opening I32c is provided to protect the working parts from injury and may be of any suitable shape.

When the switch which controls the solenoid I30 and the thermostatic control-member I3I, is closed, the member I3I will operate to cause the movable member I29 to pull on the link I25 opening the shutters I23. As the control member,

I3I breaks the circuit, the spring I26 causes the shutters to close. This alternate opening and closing of the shutters causes the interruption of the operation of the siren to produce noise, at the same time permitting the operation of the siren to continue.

When controlled by a single switch the motor is caused to operate continuously while the signal is being sounded. With the siren stator and its coacting parts in operation, an interrupted signal is in continual operation until the circuit is broken.

Referring now particularly to Figs. '1 and 8, 220 illustrates the motor of the siren and 22I its stator.

On the intake side of the siren stator is a plate 222 to which is attached the tubing 223. With-- in the tubing 223 is a valve 224 which is pivoted in the wall of the tubing 223. On an extension of one pivot is mounteda bell crank arm 224a. This bell crank arm moves the valve 224 toward open and closed position to increase or decrease the amount of air permitted to enter the tubing 223, as will be presently described. Stops 225 and 22,6 provide limits of movement in the open and closed positions respectively.

In order to operate the crank arm 224a, I provide an exhaust-operated unit having a casing 221. Within the casing 221 is a blade which wipes through an arc in a suitable chamber 229 in the casing 221. To the pivot of the blade 228 is secured an arm 230 which moves back and forth over the bell crank 224a.

A suitable valve mechanism is provided in the valve casing 23I. A shut-off valve 232 connects and disconnects the valve casing 23I with a source of exhaust as the intake of an internal combustion motor through the inlet 233.

The operation of the valve within the valve casing 23I, alternately places the sides of the the motor 320 operates.

6 chamber 229 on-opposite sides of the blade 228,

in connection with the atmosphere and exhaust,

nected at one end to the end of the arm 230 and at its other end to the bell crank arm 224a. It

is to be noted that as the arm 230 starts to move about its center, the spring 234 will be expanded. No movement of the bell crank arm 224a will take place until the axis of the spring passes through the plane containing the axis of the bell crank arm end and the axis of the pivots of the valve 224. As soon as this passing takes place, the valve 224 is quickly moved to its other extremity. This same action is reversed when the arm 23! moves in the. opposite direction, the valve 224 being moved to its original position. As the arm 230 arriving at its extreme position reverses the valve in the valve casing 23I, this movement of the arm 230 in reversed directions, moving the crank arm 224a and the valve 224, continues as long as the cut oif valve 232 is open and the exhaust is applied.

Referring now particularly to Figs. 9 and 10, the number 320 designates the siren motor and 32I the stator.

Secured to the top of the frame of stator 32i is a bracket 322. Pivotally mounted on the bracket 322 is a cam 323 having a cam groove see. On the edge of the inlet side face of the stator, are mounted a pair of complementary wing valves 325, 326, pivoted respectively at 325a, 3260a.

The cam groove 324 is elliptical in shape. Arms 3251), 32% extend from the wing valves 325, 325 and have small rollers at their respective ends, in opposite sides of the cam groove 324. When the ellipse is in the horizontal position as shown in Fig. 10, the wing valve members 325, 328 are in closed position and when the elliptical cam is vertical, the wing valve members 325, 326 are in open positions.

The cam member 323 which carries the cam groove 324 is mounted on a shaft 321 having at its other end a bevel gear 328. This bevel gear 328 is in mesh with another bevel gear 329. The bevel gear 329 is mounted on the shaft330 which carries at its lower'end a worm wheel 33 I.

The worm wheel 33I is in coactive operative engagement with a worm 332. This worm 332 is mounted on an extension of the siren shaft as shown at 333 in Fig. 9. v

Brackets 334, 335 are provided for support of the bearings for the shafts 321, 330.

It will be noted in the form illustrated that whenever the motor 320 is in operation the valve members 325, 326 are in alternate opening and closing operation. This will continue as long as While a single motor operates both siren and valveS. this is not necessary.

In Figs. 11 and 12 is ilustrated the invention applied to a constantly rotating automobile fan belt shaft.

The numeral 400 designates the motor block from which extends the shaft 40I. On this shaft is mounted the conventional V-pulley 402 to rotate therewith. Supported on the shaft 402 but non- 7 rotatable therewith, is the siren-stator 40-3, which has bearings 404a with the shaft 401! andis presvented from rotation bythe jaws A0341 in contact, with the bar 404. This bar-4,04 ismounted rigidly on the block 400;

The usual rotor of the siren is mounted on the shaft 40! to rotate therewith and carries the usual fan blades 405,

Mounted on the non-rotating stator ,403 is a bracket 406 which carries a solenoid 401. This solenoid 401 has a movable member or plunger 408 which is connected tangentially as at Mild to a band 409 surrounding the siren stator. V This band 469 has openings corresponding to theiopenr ings of the stator and when moved one space will close, or open, all of the openings of the stator.

A suitable thermo-electric control member Mil is mounted on the opposite side of the bracket 406 and is electrically connected toiihe solenoid 4D! to cause the latter to be energized and, deenergized alternately and automatically, when the current is turned on. A spring A41! connects. the band 409 with a rigid portion of the motor as the rod 404 to return the .ba-ndto the point Where the interruptor openings will "be .olosecl.

When current is put on through thethermoelectric device 4!!! the latter will operate to energize and deenergize the solenoid 40'], causing the solenoid to alternately pull, the bandAUS toopen position and then release itfor. closure by the spring M I. i

In this form the rotor of the siren j's inoperation as long as the motor lflflioperates, the siren sounding only when the band 4li9-is .movedaby' the solenoid plunger 488.

While various modifications of the invention have been illustrated and described, it is to be understood that the disclosures are merelyillustrative and that modificationsand changes may be made without departing iromtthe spirit of .theinvention and Within its scope .asolaimed.

Having describedmy. invention,-.what Iolaim is:

1. A sound device comprising a siren having an air passage, means for automatically alter.- nately increasing and decreasing the amount of air progressing through the siren includin a valve in the air passage, a circularly shaped pneumatic controller having an, opening :and :a hinge at one side, the air passage toz the siren passing through the pneumatic controller.

2. A sound device comprising .a. siren haning an air passage, .means for automatically alt-ernately increasing and decreasing the amount of air progressing through the :siren including a valve in the air passage, :a circularly shaped pneumatic controller having an opening and .a. hinge at one side, the air passage tothelsiren passing through the pneumatic controller, -a

crank means attached :to the-valve and means:

between the crank means andthe movable;mem-- ber of the pneumatic controller to alternately move the valve in oppositadirections.

3. A sound device comprising ,agsiren having an air passage, means for automatically ,-alter-- nately increasing and decreasing the amount of air pro r ssing through the siren including a valve in the air passage, a circularly shaped Pneumatic controller having an opening and a hinge at one side, the air passage to the siren passing through the pneumatic controller, a crank means attached to the valve and means between the crank means and the movable member .of the power pneumatic to alternately move the valve in opposite directions and means including a pneumatic connection, between the siren air passage and the pneumatic controller and enacting with the valve to automatically re-v verse the operation of the pneumatic controller.

4. A sound device comprising a siren having an air passage, means for automatically alternately increasing and decreasing the amount of air passing through the siren comprising a valve in the siren air passage, 2. circularly shaped pneumatic .Qontroller having an opening, the air passage to the siren passing through the pneumatic controller, a crank. means attached to the valve, resilient means having-one end connect.- ed to the pneumatic controller and the other and connected to the crank and mounted to he ononeside of the valve axis when the pneumati controller is inflated and on the other when it is, deflated and means including a pneumatic connection between the siren air passage and the pneumatic controll r and-enacting with the valve to automatically reverse the operation of th pneumatic contro ler.

;5; ,A sound device comprising a siren having an air passage, means for periodically and alter.- nately permitting and stopping the passage of airgthrollgh the -pass age t0 the siren including an automatically controlled valve means, the siren and valve means being operatively connected to and-operated from :the same air powersource.

1 A sound device comprising a sirenhaving an air passage, means for periodically andalternately permitting and stopping the passage of ir throughthepassage to the siren including. an automatically controlled valve means, the automatically controlled .valve means :having an air pressure lconnectiongtoi and operated from the pressure in the passage.

,DQN D D. :RIfI CI-IEY. REFERENCES CITED l he following references file' of this patent! UNITED STATES PA'IEENYIS are of record in the Numb er 

